April 9, 2019

Have you ever wondered what happens to your old mobile phone number?

Have you ever stopped to think about what happens to your old mobile phone number after you have decided to change to a new number?

Between the burner phones you might have used at music festivals to the numbers you might have lost due to contract terminations, you can easily accumulate a long list of mobile numbers during your lifetime.

The latest data compiled by GSMA Intelligence, a mobile data analysis group, revealed that there were 5.13 billion mobile subscribers worldwide as of March 2019. That number equates to more than two-thirds of the population in the world having a mobile connection.

Because of the huge number of mobile subscribers, UK networks are facing increasing pressure to acquire new numbers to allocate to new subscribers. Since there is a fixed pool of 11-digit combinations that begin with an 07 prefix, mobile phone service providers must recycle mobile number to meet customer demand.

Communications regulatory authority Ofcom provides UK network providers with mobile numbers in blocks of 1000, and the providers then distribute those numbers to new customers according to their own allocation plans. Ofcom is also the agency responsible for regulating how mobile phone numbers are recycled.

Ofcom maintains a strict “use it or lose it” practice regarding Pay As You Go (PAYG) phone numbers. This policy means that each mobile phone network provider has the authority to suspend the number associated with an account that is no longer active and reassign it to a new customer to ensure the efficient use of mobile numbers.

Ofcom’s policy squares with the growing practice of network providers distributing to their customers free PAYG sims that already have numbers assigned to them. Although many customers never actually activate those sims, this practice adds to the growing tally of allocated mobile numbers that would otherwise remain dormant.

The amount of time between the termination of a number and recycling it differs between networks. For example, O2 waits 12 months before recycling a terminated number. The company notes that it has internal processes and criteria that it uses before it recycles a number and that in some cases, recycling may occur more than 12 months after termination because the criteria for recycling had not been met.

Vodafone follows a similar process, but it only waits 90 days before recycling a number. However, the company does take measures to ensure that the recipient of the recycled number is not inundated with messages meant for the number’s previous owner.

However, recycled numbers can become problematic for the recipient, as many apps, including Gmail and Facebook, use your mobile number for password recovery or as an alternative way to sign into your account.

That process also constitutes a similar risk regarding the exposure of your contact details to the recipient of the recycled number. Many apps now use mobile phone numbers as an additional way to provide security to an account. Therefore, if you change your number but fail to update your phone number in the app’s settings, it’s quite possible that if the new owner of the number uses the same app, that person could see your profile when entering that phone number to access the app.